We are interested in how bacteria and bacterial products shape the development of subsequent innate and adaptive immune responses with the goal of understanding how these host-microbe interactions influence pathogenesis of infections, autoimmunity, allergy, and cancer. Our previous work has shown that cholera toxin, a mucosal adjuvant and the agent responsible for the diarrhea caused by Vibrio cholera, induces a Th17 response characterized by CD4 T cells that secrete IL-17. In 2009, we have established that this induction of Th17 cells is critical for the protective adjuvant effects of cholera toxin in a novel vaccine against a murine model of inhalation anthrax. We have also explored the mechanisms involved in induction of this Th17 response, identifying novel pathways in dendritic cells and T cells that contribute to differentiation of naive T cells into Th17 cells. These studies enhance our understanding of the mechanisms controlling T cell differentiation and identify potential pathways that can be targeted to enhance vaccine efficacy against cancer and infectious diseases.